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Lasrick sends this quote from the Bulletin of the Atomic Scientists:
Most people would agree that keeping track of dangerous material is generally a good idea. So it may come as a surprise to some that the arrangements that are supposed to account for weapon-grade fissile materials—plutonium and highly enriched uranium—are sketchy at best. The most recent example involves several hundreds kilograms of plutonium that appear to have fallen through the cracks in various reporting arrangements. ... [A Japanese researcher discovered] that the public record of Japan’s plutonium holdings failed to account for about 640 kilograms of the material. The error made its way to the annual plutonium management report that Japan voluntarily submits to the International Atomic Energy Agency ... This episode may have been a simple clerical error, but it was yet another reminder of the troubling fact that we know very little about the amounts of fissile material that are circulating around the globe. The only reason the discrepancy was discovered in this case was the fact that Japan has been unusually transparent about its plutonium stocks. ... No other country does this.

1) It wasn't 640kg of plutonium. It was 640kg of fuel rods that contains a much smaller amount of plutonium2) They were at Fukushima the whole time.3) The "Dude, Where's My Plutonium?" spreadsheet didn't have a column for "Halfway loaded into a reactor that just got hit by a tsunami"4) The plutonium bean counters noticed that SUM() didn't include the new column.

Let's not make a big deal out of this. 640kg of reactor-grade plutonium is only enough for a bit over 100 fission bombs / fusion bomb first stages, merely enough to make the recipient roughly tied for being the world's sixth most armed nuclear power.

I was thinking some hardliners in Japan's military might have stashed it somewhere, "just in case" it's ever needed.

Considering Japan has been having on-off again discussions internally about amending the constitution to allow a non-defensive military for the last 10-12 years it wouldn't surprise me. Especially now that China is/has become the largest belligerent in the region.

According to another post [slashdot.org] this plutonium could not be used to make a bomb, and the explanation makes sense to me. So even if they change the constitution they won't be making any bombs, at least not with this plutonium.

Japan has the technology to develop an atomic bomb quickly. They have an elaborate network of uranium enrichment facilities that can relatively easily make bomb grade uranium, even more so now they are using a lot less nuclear power. Plutonium is unlikely, since they don't have breeder reactors, and the plutionum like this they have is due to irradiation of uranium in light water reactors. This Pu cannot be purified to bomb-grade, since it is a mix of very many isotopes.

According to another post [slashdot.org] this plutonium could not be used to make a bomb, and the explanation makes sense to me. So even if they change the constitution they won't be making any bombs, at least not with this plutonium.

The point of a nuclear attack is to incapacitate the enemy. You never fire just one nuclear missile; you fire enough to keep them from responding in-kind. A dirty bomb attack is like kicking a hornets nest.

Plutonium has a half life somewhere between thousands and millions of years. It's too stable for use as a dirty bomb. For something to be a radiological threat it would have to have a half-life on par with a human lifespan, or much shorter.

Typically a dirty bomb is used to scare or kill people off long enough that the area is abandoned but not so long that the attacker could not take over the area for their own use. Even if the attacker did not want to make use of the bombed area, and just wanted to deny

Disaster was averted so narrowly! He was busy defending christianity from the looming threat of pagans on Fox News that day, and couldn't have been lost along with the plutonium to cause the apocalypse. Simply a scheduling conflict. Does Tuesday the 29th work out better for you?

Except that "reactor grade" plutonium is unsuitable for weapons, and cannot have the undesired isotopes of plutonium separated out of it to make it weapons grade. There's a reason why the US built the special reactors at Hanford for weapons production - you can't just make material suitable for weapons in any commercial generating station.

Except that it was never lost, and you'll find that not in the summary, but midway through TFA where it says they just entered it in the wrong column on a spreadsheet . Disaster averted. Spreadsheets are actually tools of terror!

Exactly. "No plutonium was actually lost, and the IAEA was quick to confirm that its own safeguards, which are there to ensure that no nuclear material is diverted, were applied at all times".

More worrying is the admission that "[a]s it turned out, the Genkai plant’s internal accounting system could not properly deal with such a situation, and the material ended up in the wrong column on a spreadsheet".

Spreadsheets are probably not appropriate for such critical applications. Their deceptive simplicity

What kind of a better replacement that clerics involved in rotating those numbers en masse on continous basis are you suggesting? As far as I know, spreadsheets are used because they are pretty much the best tool we have for the job that meets the sum of all requirements better than any known alternative.

You seem to think that double entry bookkeeping doesn't require extra work (significant increase in costs), that it wouldn't reduce usability (far more difficult to produce reports on wider issues), or that it would make system immune to human errors.

Entering? Yes. Reading and managing with numbers? No. You seem to think that the only costs with data management are entering. That's just ridiculous.

I'm not going to even bother with the rest of your argument, which amounts to "spreadsheet bad for everything, world is wrong in choosing it, I stand alone as a warrior for just cause". Good luck with that.

Though in this case, it also highlights a degree of redundancy. No material was actually lost, but there where multiple spreadsheets and a data discrepancy discovered during a audit. This triggered an alarm and an investigation, the system failed safe. Maybe that was a high degree of wasted effort over a false alarm, but it would appear to add an extra layer of security against data manipulation to hide deliberate theft.

You jest, but they actually are - a lot of terror groups use them to keep track of funding and expense tracking (Al Qaeda being one of them), and ironically, for corruption protection. Because they're not necessarily flush with cash, and keeping spending down and wise means your terror group can do more with less.

Basically, a terror group happens to also be a business and businesses need to keep track of their accounts.

Actually you can, you just need short refuel times to avoid burnoff in a LWR and some reprocessing. Also with proper cooling you can use reactor grade Pu in weapons ( late 50's it was successfully tested ).

I would think you could also separate the Pu-239 from the "useless" Pu-240 with a well tuned cyclotron, much like grabbing the U-235 from U-238. It would probably be easier and faster to just short fuel cycle a LWR and reprocess than separate the fuels with a single neutron mass difference though.

The mass difference between Pu 239 and Pu 240 is so insignificant that it is completely infeasible to use any current production isotope separation techniques (gaseous diffusion, centrifuges, etc.) and Pu 240 reacts to chemicals exactly the same as Pu 239, so you can't cheat it by using a chemical bath to dissolve the stuff you want / don't want (PUREX). There are experimental techniques, but they are so unreliable or expensive that it's cheaper and faster to just build a reactor to make the stuff if you'r

The most likely explanation is that it was syphoned off by the Japanese government for a secret nuclear weapons programme. While they don't want to have actually weapons right now they do want to maintain the ability to build them in short order. Their space programme provides delivery vehicles.

Reading the TFA pretty much tells you that your "likely explanation" is the exact opposite of what actually happened.

Hint: a cleric sitting in his office somewhere filing lots of reports accidentally pasted the wrong number into the column. Woops. Clearly, a government conspiracy to create nuclear weapons from material that you can't make any from in the first place.

Reactor grade plutonium is useless for bombs, and parroting the lie doesn't change that. See Dr. Helen Caldicott: Toilet Paper & Plutonium at 5:50 [youtube.com]. (The other Caldicott videos by Thorium Remix [youtube.com] also offer further insight into a prototypical leader of the anti-nuclear movement. The source of this story, "The Bulletin of the Atomic Scientists" belongs in the same class and deserves similar scorn for their rampant intellectual dishonesty.)

Let's not make a big deal out of this. 640kg of reactor-grade plutonium is only enough for a bit over 100 fission bombs / fusion bomb first stages, merely enough to make the recipient roughly tied for being the world's sixth most armed nuclear power.

Nothing to see here.

Clearly, you have never built a fission device, if you think you could get that many of them out of 640kg of even weapons grade Plutonium. You need to probably go back and read "The Curve of Binding Energy" and recalculate the neutron numbers to determine critical mass, assuming a pareto optimal design, because you are more than a bit high with "100"...

You could build a lot of dirty bombs with something like that, but you are likely better off just robbing a radiomedicine unit at a large research hospital

From TFA: "No plutonium was actually lost,... the material ended up in the wrong column on a spreadsheet."

That's because all Pu isn't created equal. It begins as some Pu in a used fuel element. It can be separated to become elemental Pu, which is somewhat dificult. The Japanese incorporate this into MOX fuel, from which it could easily be separated again (which would be pointless, but never mind). And then the MOX fuel is used, and the Pu (both old and new) becomes difficult to isolate again. This particular 640kg of Pu is in the form of an unused MOX core for a reactor which was scheduled to be started, but due to the hasty shutdown of all nuclear power in Japan after March 2011 never was. So the Pu in the unused core ended up in the books as a used MOX core.

Moreover, Podvig hints that this is about weapons grade material. It's not. Japan doesn't have a (working) fast breeder, no Hanford-style Pu production reactor, and no Magnox-style dual purpose reactors. This Pu is from light water reactors, therefore heavily irradiated, therefore isotopically a mess, and therefore not weapons-grade and never going to be weapons grade by any means. But Podvig makes a living off the case of nuclear non-proliferation, so of course desaster is looming, or he wouldn't have a job anymore.

Damnit Microsoft, when are you going to finally include a Plutonium macro in Excel!

Well this is the thing: for years, most of the requested features in Office have actually already been in there, but people simply didn't realise. Trust me, it's in there somewhere, but you have to be an expert at navigating the ribbon to find it.

Damnit Microsoft, when are you going to finally include a Plutonium macro in Excel!

Well this is the thing: for years, most of the requested features in Office have actually already been in there, but people simply didn't realise. Trust me, it's in there somewhere, but you have to be an expert at navigating the ribbon to find it.

That's why they need to bring back that Paper clip.... "I see you are trying to find Pu.... "

Sellafield in the UK lost nearly 30 kg of plutonium [wikipedia.org] in 2005. But that was on paper only.....except the plutonium washed out to sea [theguardian.com]. Of course it can't enter the human food chain can it? [theguardian.com]

If I'm reading that right, the material wasn't lost, it just couldn't be accounted for after deliberate disposal because they made some seriously incorrect assumptions about how it would sequester itself in the environment. So that's a different issue.

They stored their plutonium stockpile carefully (also because packing it too tight is a very bad idea), but they were not aware that it was made of Pu-233 [periodictable.com]. This explains why the stockpile they bought was sold at such a bargain price on the market...

Regarding the lost 1410 lbs of the deadliest substance on Earth,By what metric do you declare Plutonium to be the deadliest substance on Earth? I only ask b/c not all Plutonium is created equal, and if the stuff remains Pu for ~100 minutes is it really all that deadly?

You will notice that while Dr Cohen offered to consume as much plutonium as you would caffeine, he never actually did so.

The annals of the history of science are littered with cranks.

Dr Cohen also said that he believed uranium to be a renewable resource. Unless he's figured out a way to grow uranium, I'm sure you'll agree there is a finite amount of the substance. Dr Cohen did not believe that the amount of uranium on Earth was finite.

He was pointing out that we attach irrational levels of fear to some substances, while are completely unconcerned about consuming significant (if not deadly) amounts of other toxins. I don't know what the 'most deadly substance on earth' is, but there are plenty of things that will kill you at the mg level.

If you define 'renewable' to mean it will never run out then there is no such thing as renewable energy.

Speaking as an ignorant and unimportant foreigner, I wonder why - in view of the previous two posts - more of you Americans don't vote for parties other than Republican or Democrat. That way you might get a government that rules in your interest, as citizens.

I don't suppose anyone will even read this reply, but surely yours is an argument of despair? Moreover, isn't it slightly circular? And it certainly doesn't speak well for the health of democracy. If no party other than the two giants has any chance of being elected, what happens to the citizens' power to elect a government that will carry out their wishes?